Zika Virus may Hold the Key to Treat Brain Cancer

Zika virus could be a promising treatment for glioblastoma, which is the most common form of brain cancer, finds a new study.

Highlights:

The Zika virus, which has caused birth defects could be used to treat glioblastoma, which is the most common and aggressive forms of brain tumor
The virus can destroy glioblastoma cancer cells in the same way it attacks the developing brains of fetuses
The findings could lead to the development of new, effective treatments for this type of brain tumor

Zika virus has been linked to birth defects in unborn children. But a new study has found that Zika virus could be used to target and kill cancer cells in the brain. The study conducted by a research team from Washington University School of Medicine in St. Louis and the University of California, San Diego, is published in The Journal of Experimental Medicine.

The most common form of brain cancer is glioblastoma, which is lethal. Most of the patients with glioblastoma die within two years of diagnosis. The growth and development of glioblastoma are driven by stem cells that proliferate and give rise to other tumor cells. It is hard to kill glioblastoma stem cells as they can avoid the body’s immune system and are resistant to chemotherapy and radiation. Glioblastoma can be surgically removed. However, it is important to target and kill glioblastoma cells to prevent the recurrence of new tumors.

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Glioblastomas are tumors that arise from astrocytes that make up the supportive tissue of the brain. Glioblastomas are usually highly malignant.

‘Zika virus is effective at targeting and killing brain cancer stem cells. It could also be used to develop effective treatments for glioblastomas.’

"It is so frustrating to treat a patient as aggressively as we know how, only to see his or her tumor recur a few months later. We wondered whether nature could provide a weapon to target the cells most likely responsible for this return," says Milan Chheda from Washington University School of Medicine in St. Louis.

Can Zika Virus Kill Hard-to-Treat Glioblastoma Cells?

Currently available treatments for glioblastoma are limited by their ability to cross the blood-brain barrier. The doses of the drugs have been kept low to avoid damage to healthy brain tissues. But, the Zika virus can cross the blood-brain barrier and could target cancer cells, opening a potential new way to treat glioblastoma.

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Zika virus is transmitted to humans by infected mosquitoes which causes mild fever with maculopapular rash. No treatment or vaccine is currently available.

Zika virus infection during pregnancy causes birth defects in babies by attacking the stem cells in the developing brain. But in adults, Zika virus causes only mild-flu like symptoms because the adult brain is fully developed. In brain tumor, the cancer cells resemble those in the developing brain, suggesting that the Zika virus could attack them too.

How Zika Virus Destroys Glioblastoma Cells

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Cancer stem cells can be killed using viruses that specifically target tumor cells. Zika virus disrupts fetal brain development by targeting neural stem and progenitor cells. The effect of Zika virus on the adult brain is much less severe because the number of active stem cells in the adult brain is fewer compared to developing fetal brains.

"We hypothesized that the preference of Zika virus for neural precursor cells could be leveraged against glioblastoma stem cells," says Michael Diamond, also from Washington University School of Medicine in St. Louis, who co-directed the study with Milan Chheda and with Jeremy Rich, from the University of California, San Diego and the Cleveland Clinic Lerner Research Institute.

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The Study

The research team conducted a study on mice with aggressive glioma to see how Zika virus kills brain cancer stem cells. Mice with aggressive glioma were injected with a mouse-adapted strain of Zika virus. The team found that Zika virus slowed tumor growth and significantly extended the lifespan of mice. Zika virus infected patient-derived glioblastoma stem cells compared with other glioblastoma cell types or normal neural cells.

The team also tested a mutant strain of Zika virus, which is less virulent than naturally occurring strains of the virus. They found that the attenuated strain, which is more sensitive to the body’s immune response was still able to specifically target and kill glioblastoma stem cells. The attenuated strain was even more effective when combined with a chemotherapy drug called temozolomide, which usually has little effect on glioblastoma cells.

The study represents the creative synthesis of three research groups with complementary expertise to attack brain cancer cells by harnessing the cause of another disease. “Adults with Zika virus may suffer less damage from their infection so that this approach could be used with acceptable toxicity.” said Jeremy Rich.

This study is the first step towards the development of safe and effective strains of Zika virus that is important in neuro-oncology and in the treatment of glioblastoma. However, public health concerns should be addressed through pre-clinical testing and evaluations of the strains’ ability to disseminate or revert to more virulent forms.

Reference:

Scientists to test Zika virus on brain tumours - (https://www.curebraincancer.org.au/news/1428/scientists-to-test-zika-virus-on-brain-tumours)

Source-Medindia